Drought is one of the major limitations to maize production worldwide—15% of the world's maize crop is lost every year to drought. Periods of drought stress can occur at any time during the growing season, but maize is particularly sensitive to drought stress in the period just before and during flowering. When drought stress occurs during this critical period, a significant decrease in grain yield can result.
Identifying genes that enhance the drought tolerance of maize could lead to more efficient crop production by allowing for the identification, selection and production of maize plants with enhanced drought tolerance.
As such, a goal of plant breeding is to combine, in a single plant, various desirable traits. For field crops such as corn, these traits can include greater yield and better agronomic quality. However, genetic loci that influence yield and agronomic quality are not always known, and even if known, their contributions to such traits are frequently unclear. Thus, new loci that can positively influence such desirable traits need to be identified and/or the abilities of known loci to do so need to be discovered.
Once discovered, these desirable loci can be selected for as part of a breeding program in order to generate plants that carry desirable traits. An exemplary embodiment of a method for generating such plants includes the transfer by introgression of nucleic acid sequences from plants that have desirable genetic information into plants that do not by crossing the plants using traditional breeding techniques.
Desirable loci can be introgressed into commercially available plant varieties using marker-assisted selection (MAS) or marker-assisted breeding (MAB). MAS and MAB involves the use of one or more of the molecular markers for the identification and selection of those progeny plants that contain one or more loci that encode the desired traits. Such identification and selection can be based on selection of informative markers that are associated with desired traits. MAB can also be used to develop near-isogenic lines (NIL) harboring loci of interest, allowing a more detailed study of the effect each locus can have on a desired trait, and is also an effective method for development of backcross inbred line (BIL) populations.
Maize drought is one of the major limitations to maize production worldwide. When drought stress occurs just before or during the flowering period, an increase in the length of the anthesis-silking interval and a decrease in grain yield can result. 15% of the world's maize crop, or in excess of 19 millions tons, is lost every year to drought. Identifying candidate genes that can enhance drought-stress tolerance in maize could lead to more efficient crop production in affected areas.
What are needed, then, are new methods and compositions for genetically analyzing Zea mays varieties with respect to drought tolerance and for employing the information obtained for producing new Zea mays plants that have improved water optimization traits.